Optical cables comprised of optical fibers positioned within sheaths of insulating material are priorly known. Optical fibers, in contrast to metallic conductors, are highly flexible, have minimal dimensions, and are not materially affected by ambient electric and magnetic fields. They are, however, highly susceptible to mechanical damage and should not be bent in small turns, and should be protected from tension forces.
It is priorly known to cross-link plastic outer jackets of communication cables to achieve mechanical and thermic durability. Such cross-linking may be achieved by the employment of chemical additives or high energy radiation. In the case of chemical additives, high temperatures and high pressures are usually present. These conditions render chemical cross-linking inappropriate for optical cables since there would be considerable risk of damage to the sensitive optical fibers, notwithstanding the protective plastic coatings formed thereabout. In the case of using high energy radiation for cross-linking the outer jackets of optical cables, the penetration of radiation into the optical fibers would destroy the ability of such fibers to transmit optical signals, i.e., it would render the optical fibers opaque.